Field of the Invention
The invention relates in general to an image processing device and method, and more particularly to an image processing device and method utilizing the Wireless Display (WiDi) technology.
Description of the Related Art
FIG. 1 shows a schematic diagram of a conventional image display system. An image display system 10 includes a dynamic random access memory (DRAM) 110, an image processing device 120 and a display device 130. The image processing device 120 includes an image scaling circuit 122 and an image processing unit 124. The DRAM 110 stores image data to be processed. The image scaling circuit 122 accesses image data from the memory 110, and performs a scaling process such as up-sampling or down-sampling on the image data. The image processing unit 124 then performs a process such as de-interlacing on the image data, and outputs the processed data to the display device 130 for further display.
FIG. 2 shows a schematic diagram of a conventional image display system utilizing the Wireless Display (WiDi) technology. An image display system 20 includes DRAMs 210 and 230, an image processing device 220, and a display apparatus 240. The image processing device 220 includes an image scaling circuit 222 and a multi-format video encoder (MFE) 226. After being processed by the image scaling circuit 222, the image data previously stored in the DRAM 210 is stored back into the DRAM 210. The MFE 226 then accesses the image data from the DRAM 210, encodes the accessed data, and stores the encoded data to the DRAM 230. The external display apparatus 240, e.g., a cell phone, computer or television, obtains and plays the data in the DRAM 230 via Wi-Fi.
One disadvantage of the above image processing device 220 is that, the data having been processed by the image scaling circuit 222 needs to be first stored back into the DRAM 210, and then accessed therefrom when needed by the MFE 226. In general, video data usually exists in large amounts, which may get increasingly substantial as the resolution supported by the display apparatus 240 gets higher. When processing video data, the image scaling circuit 222 performs one read operation and one write operation on the DRAM 210, and the MFE 226 also performs one read operation on the same DRAM 210. As the video data amount increases, these read and write operations may occupy a large memory bandwidth, such that signal delays are likely incurred if the speed of the memory is not fast enough. For the WiDi technology, real-time and smooth image playback is essential, and excessive delays in playback may result undesirable user experiences.